Navy

#000080

rgb(0, 0, 128)

hsl(240, 100%, 25%)

.element {
  background-color: #000080;
  color: #000080;
  border: 1px solid #000080;
}

.element {
  background-color: rgb(0, 0, 128);
  color: rgb(0, 0, 128);
}

.element {
  background-color: hsl(240, 100%, 25%);
  color: hsl(240, 100%, 25%);
}

<div style="background-color: #000080; color: white;">
  Content
</div>

element.style.backgroundColor = "#000080";
element.style.color = "#000080";

<div style={{ backgroundColor: "#000080", color: "white" }}>
  Content
</div>